Work is due to start next month on a 400-space multi-storey car park at Sandwell General Hospital in West Bromwich and a 550-space car park at Birmingham's City Hospital on Dudley Road.
Construction is set to take place over the next 12 months, with both car parks scheduled to be open by next summer.
Bosses at Sandwell and West Birmingham NHS Trust, which runs the two sites, said the extra spaces will be vital for when the new £6 million medical centre opens.
The centre, which sits next to Sandwell General Hospital, will house Carters Green Medical Centre and Lyndon Health Centre.
City Hospital is due to be redeveloped over the coming years to incorporate new housing and commercial space. It will continue to provide health services at the Birmingham Treatment Centre, the Birmingham and Midland Eye Centre and the Sheldon Block.
James Pollitt, assistant director of strategic development, from the trust, said: "The new multi-storey car parks will give the extra capacity we need at both hospital sites to ensure that patients arriving at the hospitals are able to park easily, making their visit to us as stress-free as it can be.
"The project will undoubtedly have a huge positive impact on patients, staff and visitors to both hospitals, with environmentally friendly considerations such as electric vehicle charging points built in."
The trust is working with car park operator Q-Park and its development partner Prime to progress the plans for the new car parks.